Dynamo-electric machine.



R. LUNDELL. DYNAMO ELECTRIC MACHINE.-

APPLICATION FILED rmmo, 1909.

1,045,158, Patented Nov. 26, 1912. V

INVENTOR- l'illlil l) SilAllliil HZllililllflf L'UNKSELL, (935 NEW' YGRK, 133. Y.

DYNA M Q ET.

Application filed geeifioetton of Letters Patent.

tmonmn.

Patented. Nov. 26, 19123.

. 3908. Serial No. 479,173.

N UNDELL, it

' end of it 3S 9. speoiii My weanen-tion r fi es to direct ourd in end lIlUlOl'i-i, provided with field Wind" nt LillQCiLiQlih and eerie end field, uiicb serves to reversetlie omnmutnted errnetui-e e object of the invention is to secure the advantages of ft strong oonimutoting field Without the aid of auxiliary inte1'- and further to secure the advanof on even distribution of the field at all loads (2". e. no appreciable distortion in spite of at large urmature i'eeotion) 1 cont the aid of the elubomtc compensating windings usually 'enqoloyed to ettein this desiiruble result.

M v invention consists in placing a strong ser es winding upon that portion of the pole Willfill, otherwise, "would be excessively weakened ey the armature reaction and in chokthe field flux by saturation at all points ii 1e poles and the pole-faces, where the crossenegnetizing eifeot of the armature reaction. and the field excitation would, otherwise, cause the densityof the field flux ecicoss the air-gap to becomeebnormal.

I em enabled, by properly choking the flux at such points, to make .a simple serieswinding concentracted upon a corpere'tively small portion of the pole serve the three fold purpose of commutating winding, oompenseting winding, and a winding for effecting proper compounding.

My'inveoiion further consists ina' novel arrangement of the poles and the pole-faces, by which a ,section of the pole-face, which is smbjecl ed to an excess of combined Ina-gnaw-motive force, is caused to distribute its excess fiuxthrough enotheradjacentsecesident of tion, which is suffering from a lack of oilficient magneto-motive force.

The invention also comprises certain novel arrangements of the various details for oi tecting; improved ventilation and a saving of space and material.

My present invent on is a. direct improve ment upon an earlier invention described by me in U. S. Patent No. 571,310 of Nov,

i bi? which the shifting or the distortion of t magnetic field at full loedwes in e measure overcome.

The invention can also be seid to be on it npyoveinent upon those forms of direct ein'z'ent machines in which series fie d coils are wound over only a portion of the main pole, such forms having been suggested Swinburne in 18% (see Jown. S00. Teleg. Enginemr, XV. 542, 1886) by Hie-ham in 1889 S; Patent No. 400,680, Anvil 2nd, 1.889) b E. Thomson in 1891 isee U. S. l eten: o. 9259, 122, Sept. 15th, 1891) end others.

The piesent pi'oblein however, was not solved by any of the lOIlSiOYlDS above referred to, beczwse, lie series winding in any of these forms made sufiioiently powerful to serve as e. con-mutating and a.

compensating Winding, such machines would sufier either from excessive over-compounding 01 from excessive distortion of the field flux, or from both of these defects.

It will be understood by those skilled in the art that, in order toobtain a positive commutating field, the magneto-motive force of theermature at the points of commutation must not only be fully neutralized, but must be over-balanced by considerable amount, so that there will be a positive oomnluteting flux thrown back over the coils which are undergoing commutation.

My invention will best be understood by reference to the accompanying drawings, in which,

Figure 1 illustrates in side elevetional View a portion of a multi-polai dynamo electric machine, the upper pole witli its field coils being shown in section. Fig. 2 is a sectional View of the machine taken on the line 'X Y' of Fig. 1, looking from left to right. Fig. 3 is a sectional View of one o too great a dip in the curve would cause addit-ional iron losses in the armature teeth. hence it is of importance til; it the fullload induction curve should be as even as pos sihle. By magnetically bridging the space between the two pole-shoes say by a small iron strip as indicated by 8 in Fig. 4-, it be comes possible to lower the induction at the inner corner of the pole-shoe 5. where it is too high, and to raise the induction at the inner corner of 6, where it is too low. But there is danger of disturbing the con'nnutation field at the outside corner of pole-shoe 5 by such means, unless the small pole or pole-shoe be divided into a saturated and an alert portion. liig. 6 shows such an arrangement, v The two pole-shoes 5 and 6 are here magnetically united and the section marked 10 of the small pole-shoe is of such cross-section relative to its corresponding pole surface that it is highly saturated at no-load, same as the portion marked 13.

Section 10 of the smaller pole-shoe, which at full load is subiected to an excess of magnetoi otive force, is in this manner caused ibute its excess of flux through the adjacent section 11 of the large pole-shoe, which at :tull load suffers from too small a magneto-motive force. The final resultis an improvement in the full load induction curve cl, as indicated in Fig. 6.

In very large and highspeed (turbine driven} generators, the series winding may in addition be divided or distributed upon two small cores, as shown by Fig. 5, the outer core having about twice as many ampore-turns as the inner 'core.v

It will be understood that the crossseo tion of the smallpole core is made of such dimensions that the series-ampere-turns around the same, which are necessary for proper over-compensation of the BL M. F. of the armature, will, in addition, be justsutlicient to effect proper compounding. It the small portion of the pole is made 'very small as compared to the large portion there would be no compounding at all and the series winding would serve the sole purpose ofa 'commutating winding. This arrangement would be useful in connection with a constant speed motor which is to run in only one direction.

Having thus described my invention what I claim and desire to secure by Letters Patent of the United States is 1. A dvnamo electric machine havingeach of its poles divided into a small and a large portion, a series winding surrounding the said small portion and a shuntwindiug surrounding both of said portions; in combination with laminated pole shoes which practically close the space or opening between the said polar portions at their pole-face surfaces, substantially as described.

incense 2. A dynamo electric machine having its pole cores divided into a small and a large portion, the latter being providedwith a polar extension which materially increases its pole-lace area; in combination with a series winding around the said small portion and a shunt Winding surrounding both of the said portions as well the said series winding, substantially described.

3. A dynamo electric machine having its pole cores divided into a small and a large portion, the latter being; provided with a polar extension which materiallincreases its pole-face area; in combination with a series winding aroundthe said small portion, a shunt winding siiirrounding both of the said portions and means for magnetically connecting the inner pole-feces of the said smalland large portions, substantially as described; I

4. A dynamo electric machine having eachof its poles divided into a small and a large portion said polar portions being in turn subdivided close to their pole-faces into two or more minor portions or sections; in combination with means for magnetically connecting the pole faces oi. the said small and large portions, substantially as and for the purpose described.

A dynamo electric machine having each of its polesdivided into two distinct portions, one of said portions being of less width in the direction of the shaft than the second portion, said second portion being subdivided close to its pole-face into two I 100 or more minor portions or sections and provided withja polar extension which materially increases its pole-face area; in combination with a series winding surrounding the first mentioned polar portion and a shunt winding surrounding both of said portions, substantially as and for the purpose described.

6. A dynamo electric machine having each of its pole-cores divided into one or more smallportions on one side of the pole and a large portionon the opposite side of the pole, said large polar portion being subdivided close to its pole-face into two or more minor portions or sections; in combination with means for magneticallyconnecting the pole faces of the said small and large portions, substantially as and for the purpose described.

7. A dynamo electric machine having each of'its poles divided into a smalland a large portion,said polar portions being in tum subdivided close to their pole-faces into two or more minor portions or sections; in combination with a series winding surrounding the first mentioned small polar portionand a shunt winding surrounding all of said portions, substantially as and-for the purpose 8. A dynamo electric machine having its shunt winding, substantially as shown and to pole cores divided into a large and a small portion, the smaller portion being of less Width in the direction of the shaft than the larger portion; in combination with a series winding around the said small portion, a

shunt winding surrounding both pole cores as Well as the said series winding, and providing air spaces on the lnner sides of the l t l r i l i l t l memes described.

In testimony whereof I have signal my name to this specification in the presence" of two subscribing witnesses.

ROBERT LUYDELl'i.

Witnesses M. F. Knn'rnvo, H. J. SOHUTTE. 

